A shared laugh can soften a disagreement without settling the thing that caused it.

Laughing together in the middle of an argument does something real. It reminds both people that they are not enemies, lowers the temperature, and makes the next sentence easier to say. What it does not do is resolve the disagreement, though it can feel enough like resolution that everyone quietly agrees to stop.

Take the relief for what it is and come back to the subject when you are both calm. Say something like: that was better, and we still have to sort out the actual thing. Warmth and unfinished business can share a room.